If you're running Windows 8 or Windows 7, the best way to tell if your PC and connected devices are ready for Windows 8.1 is to download and run Windows 8.1 Upgrade Assistant, which scans them and tells you if there is anything you'll need to do before or after updating.

If you're running Windows Vista or Windows XP, you can use Windows 8 Upgrade Assistant to see if your programs and devices are compatible with Windows 8, since most programs and devices that work in Windows 8 will also work in Windows 8.1. If you're running Windows XP, you need to have Windows XP Service Pack 3 (SP3) installed to use Windows 8 Upgrade Assistant. For more info, go to the Service Pack and Update Center.

But you should still check the system requirements. We also recommend that you visit your PC manufacturer's website for info about updated drivers and hardware compatibility.

If you're running Windows 8, you need 3,000 MB of available space for the 32-bit version of Windows 8.1, and 3,850 MB of available space for the 64-bit version of Windows 8.1. If you're running Windows 7, we recommend that you run Windows 8.1 Upgrade Assistant to check if you have enough available space. If you're running Windows Vista or Windows XP, we recommend you check the system requirements before installing Windows 8.1.

You need a total of 16 GB (32-bit version) or 20 GB (64-bit version) of space on your hard drive for Windows 8.1.

If you start (boot) your PC from installation media that you created when you downloaded the ISO, such as a DVD or USB flash drive, you won't be able to keep your apps, Windows settings, or personal files when you install Windows 8.1.

This table shows what you can keep when you update, depending on the version of Windows you currently have running on your PC.
To verify which version of Windows you have now, see Which Windows operating system am I running?

If you're running

You can keep

If you're running

Windows 8

You can keep

Windows settings, personal files, and most apps

If you're running

Windows 7

You can keep

Personal files

If you're running

Windows Vista

You can keep

Nothing—you must boot from media and perform a clean installation

If you're running

Windows XP

You can keep

Nothing—you must boot from media and perform a clean installation

If you're running Windows 8, your Windows Store apps will need to be reinstalled from the Store. For instructions, see Welcome to the new Windows.

If you're running Windows 7, Windows Vista, or Windows XP, all of your apps will need to be reinstalled using the original installation discs, or purchase confirmation emails if you bought the apps online.

If you're updating from Windows 8, you can use Windows 8.1 Upgrade Assistant to check your desktop apps and connected devices—most desktop apps, devices (like printers), and network connections will work normally after the update. You'll need to reinstall your Windows Store apps. For more info, see Update to Windows 8.1 from Windows 8.

If you're running Windows 7, you can use Windows 8.1 Upgrade Assistant to check if your programs and devices are compatible with Windows 8.1. Or, if you're running Windows Vista or Windows XP, you can use Windows 8 Upgrade Assistant to see if your programs and devices are compatible with Windows 8. Most programs and devices that work in Windows 8 will also work in Windows 8.1. If you're running Windows XP, you need to have Windows XP Service Pack 3 (SP3) installed to use Windows 8 Upgrade Assistant. For more info, go to the Service Pack and Update Center.

No. If you want to install Windows Media Center, you need to add features to Windows 8.1. If you're already running Windows 8 Pro and have Windows Media Center, you won't need to reinstall it after updating to Windows 8.1. For more info, see the Add features webpage.

If you already have third-party DVD playback software in Windows 8, you should be able to keep using it in Windows 8.1. If you're running Windows 7, Windows XP or Windows Vista, you'll need to reinstall it.

If you don't have a third-party app that plays DVDs, or if you currently rely on Windows Media Player for DVD playback, you'll need to download and install a third-party app or install Windows Media Center to play DVDs.
For more info, see the Add features webpage.

Note

If you're running Windows 8 and have a language pack or a language interface pack (LIP) installed, they'll be removed when you install Windows 8.1.
For more info, go to the reinstall language packs article.

If your PC has a 64-bit capable processor (CPU) but is currently running a 32-bit version of Windows, you can install a 64-bit version of Windows 8.1, but you'll need to buy it as a DVD and perform a clean installation. You won't be able to keep any files, settings, or apps when you update from a 32-bit to a 64-bit version.

Please note that the Windows 8.1 Pro Pack is used to upgrade from Windows 8.1 to Windows 8.1 Pro, and isn't for cross-architecture installs and doesn't include any media. If you want to change architectures, buy Windows 8.1 Pro.

For more info about what service packs are available, see Add features.

You can buy a Windows 8.1 DVD from the Microsoft Store or any other retailer if available in your country or region.
You can also buy it online from the Microsoft Store in Austria, Belgium, Canada, France, Germany, Ireland, Italy, Japan,
Netherlands, Denmark, Finland, Norway, Sweden, Spain, Switzerland, United Kingdom, and
United States.

If you want to build your own PC and install Windows 8.1, or want an additional operating system running in either a local virtual machine or separate partition (including a Mac), you can buy the Windows 8.1 products (full version) from a local retailer.

If you're running Windows 8, you'll likely see a periodic notification to update to Windows 8.1. The first time you receive the update notification, you'll have the option to go to the Windows Store where you can begin the process of updating to Windows 8.1. If you dismiss the notification, you'll receive reminders once a week for the first month, and then twice per month until you update.

You won't see the update notification if:

Your PC isn't eligible for the Windows 8.1 update through the Windows Store (such as a PC running an Enterprise version of Windows 8).

You tried to update to Windows 8.1 and had a problem that caused you to roll back to Windows 8.

If you recently used Add features to Windows 8 to get an edition of Windows with more features, you might see an error message if you immediately try to update to Windows 8.1 in the Windows Store. To solve this problem, you can try clearing the cache for the Store on your PC.

Swipe in from the right edge of the screen, and then tap Search.(If you're using a mouse, point to the lower-right corner of the screen, move the mouse pointer up, and then click Search.)

Enter run in the search box, and then tap or click Run.

Enter wsreset.exe in the Run command and then tap or click OK.

Note

If you have touch input hardware that isn't specifically designed for Windows 8.1, but is compliant with the Windows Certification Program for Windows 7, you can upgrade to Windows 8.1 and will experience touch responsiveness at least as good as it was on Windows 7. Because Windows 8.1 touch requires a higher degree of responsiveness and precision, Windows 8.1 touch PCs that qualify for the Windows Certification Program provide a much better experience typing on the touch keyboard and using certain features than on Windows 7 PCs. For example, certain Windows 8.1 features and apps won't work on touchscreens that support fewer than five simultaneous touch points.

If your PC came with Windows 8 you might be able to restore it back to Windows 8 by refreshing your PC. Your personal files won't be affected, but apps that didn't come with the PC will need to be reinstalled.
For more info, see How to refresh, reset, or restore your PC.

If you were running Windows 7, Windows Vista, or Windows XP, you'll need to reinstall your previous version of Windows using the recovery or installation media that came with your PC (typically a DVD).

If you don't have recovery media, you might be able to create it before you update from a recovery partition on your PC using software provided by your PC manufacturer. Check the support section of your PC manufacturer's website for more info. After you install Windows 8.1, you won't be able to use the recovery partition on your PC to go back to your previous version of Windows.